SAN FRANCISCO (AP) - Lodging sharing service Airbnb has taken a bite out of San Francisco’s already limited stock of rental housing as some landlords and housing activists contend, a newspaper reported Sunday.

The San Francisco Chronicle (http://bit.ly/1lzyC7C ) commissioned a data harvesting company to analyze a day’s worth of Airbnb’s local listings to see what kind of places were available on the website and if the accommodations were being rented for short or long periods.

The analysis by Connotate Inc. found that almost two-thirds of the 4,798 listings were for whole apartments or houses, 160 of which appeared to be occupied full time. That is significant, according to the Chronicle, because Airbnb has been promoted as a humble service that allows people with spare rooms or those going away for a few days to generate some extra cash by participating in the “sharing economy.”

The figures suggest some property owners and managers are using the service to get around San Francisco’s strict rent control and other tenant protection laws, the newspaper said. Rentals under 30 days are illegal in the city.

“In a city that has chronic housing shortages, the number of Airbnb homes that appear to not be available on the rental market is significant,” Connotate Chief Strategy Officer Laura Teller said.

Airbnb insists the majority of its hosts are residents who occasionally share the home in which they live, and that the service has boosted the city’s economy in direct and indirect ways.

“We know Airbnb has made San Francisco more affordable for more families who use the money they earn to pay the rent and make ends meet,” the company said in a statement Sunday. “And because Airbnb listings are in every neighborhood, travelers get to see parts of the city and patronize local businesses they would have missed if they stayed in a hotel.”

Connotate could not determine from its analysis if the listed properties were rented out occasionally or all the time. More than 300 listings had enough user reviews to suggest they have “heavy or constant visitor traffic.” Similarly, while the vast majority of people placing rentals - 86.4 percent - had only one room, apartment or house listed, 513 were connected to more than one property.

Some of the multiple-listers were property managers handling Airbnb rentals on behalf of hosts who want to avoid the hassle; some were people offering two different rooms in their homes.

“From a policy perspective, the real issue is whether there are a lot of units that have been removed from the housing market because of short-term rentals,” Gabriel Metcalf, executive director of SPUR, an urban design think tank, told the Chronicle. “It looks like that’s not a big number yet, but that’s what we need regulation to control so it doesn’t become big.”

The cheapest listing was for a shared bedroom costing $18 a night, while the most expensive was a house going for $6,000 a night. The citywide average for all listings was $226 a night.

San Francisco lawmakers are discussing ways to bring Airbnb and its competitors into compliance with city law. One supervisor has introduced a bill that would legalize short-term rentals but require the renting party to pay the city’s 14 percent occupancy tax, which Airbnb says it would do starting this summer.